Lyophilization is a process used to remove water from substances allowing these substances to be stored for longer periods of time without material deterioration. Typically these substances are of biological or synthetic origin and may include antibiotics, pharmaceuticals, chemicals, sera, vaccines, cells, tissues, protein and/or nucleic acids.
Substances can be lyophilized by placing individual vials or a multi-well plate containing one or more substances into a lyophilizer, which generates and maintains a controlled environment therein during the lyophilization process. The environmental factors that are controlled by the lyophilizer include, but are not limited to, temperature, air pressure/vacuum level, humidity, and/or gas content. After lyophilization is complete, the seal on the lyophilizer is released, and consequently the controlled environment within the lyophilizer is diluted with the air surrounding the lyophilizer, which can be detrimental to lyophilized substances. A primary consequence of contacting lyophilized substances with the air from outside of the lyophilizer is that the air generally contains moisture (e.g., water vapor) which may rehydrate (at least partially) the lyophilized substances. Depending on factors such as the time of year, the room air-conditioning, the number of people in a room and the exposure time, lyophilized substances in contact with air from outside of the lyophilizer can undergo from 40% to 70% rehydration. Introducing moisture to the lyophilized substances can negatively affect the stability of the substances. If the substances are not going to be used immediately, the vials and/or wells of the multi-well plates can be sealed by placing a foil or other sealing material over the wells and/or vials, thereby sealing and isolating the lyophilized substances from the air. The seal provides a barrier between environmental conditions surrounding the plate and the substances located within each vial or well of the plate after the plate has been removed from the lyophilizer. Thus, the seal impedes rehydration of substances that results from absorbing water vapor from the atmosphere. The sealed vials and/or plates containing the one or more substances can then be stored or sold in commerce for later use. The seals can then be broken such that the stored substances within one or more of the vials and/or individual wells may be accessed during use.
The process of sealing receptacles after removal from the lyophilizer exposes the individual substances to unfavorable environmental conditions during the period of time between removal of the receptacle from the lyophilizer until the receptacle is sealed. While this exposure time can vary depending on the number of vials and/or wells of the multi-well plate to be sealed, the number of technicians available to seal the vials and/or wells, the transportation distance between the lyophilizer and the sealing station, and other factors experienced during a lyophilization procedure, the exposure time for lyophilized substances in a high-production facility may be between 4-5 hours. As a result, the lyophilized substances in each vial or well of the multi-well plate may be exposed to uncontrolled and potentially unfavorable environmental conditions, including moisture, prior to being sealed.
Prolonged exposure of the lyophilized substances to these uncontrolled environmental conditions during the period of time between removal of receptacles from the lyophilizer until the receptacles are sealed may be reduced by placing the receptacles into a glovebox (e.g., the Purelab HE 4GB 2500 Glovebox, available from Innovating Technology, Inc. Newburyport, Mass.) immediately after removal from the lyophilizer within which an operator may seal each of the receptacles. However, manipulation of the receptacles may be cumbersome when using a glove box. Additionally, the moisture vapor exposure time during transfer of the receptacles from the lyophilizer to the glovebox may still be significant and may lead to moisture absorption by the lyophilized substances. Furthermore, the environment within a glovebox cannot be made the same as the environment within the lyophilizer itself, and so the lyophilized substances remains exposed to an unfavorable humidity level for a long period of time before being sealed.
A lyophilizer may be operated within a dry room with low humidity. On removal of receptacles from the lyophilizer, substances are exposed only to the dry room prior to sealing. However, dry rooms require precision climate control systems for maintaining low humidity within a room-volume sized to accommodate at least one operator. The humidity levels are again not the same as those within the lyophilizer, though, and the mere presence of an operator within the dry room further negatively impacts the environmental conditions. Dry rooms are expensive to maintain, subject to contamination, and cumbersome to operate because conditions may be hazardous for individuals working inside of these rooms, and accordingly the amount of time an individual may work within these rooms may be limited.
Large stoppered individual vials storing a single substance can be configured for the stoppers to engage while the individual vials are located within a sealed lyophilizer However, such individual vials are difficult to manage, bulky to store, and not usually compatible with laboratory equipment designed for handling samples in a multi-well format.